I just had the exact same issue with a phone that was less than 30 days old. The phone was never dropped or damaged and had no issue besides the cracked home button. The first sign was that the touch id was not available and when I tried to push the home button to load to the home screen, the button literally cracked. I sent it to Apple only to be told that it was damage/misuse and not covered under warranty and would cost me approximately $319 (the out-of-warranty) fee for a repair!! Never buying an Iphone again...I'll stick with Samsung!